C++ transaction类代码示例

// Validate script consensus conformance based on flags provided.
static bool check_consensus(const script& prevout_script,
    const transaction& current_tx, size_t input_index,
    uint32_t options)
{
    BITCOIN_ASSERT(input_index <= max_uint32);
    BITCOIN_ASSERT(input_index < current_tx.inputs.size());
    const auto input_index32 = static_cast<uint32_t>(input_index);
    const auto bip16_enabled = ((options & validation_options::p2sh) != 0);

#ifdef WITH_CONSENSUS
    using namespace bc::consensus;
    const auto previous_output_script = prevout_script.to_data(false);
    data_chunk current_transaction = current_tx.to_data();

    const auto flags = (bip16_enabled ? verify_flags_p2sh : verify_flags_none);
    const auto result = verify_script(current_transaction.data(),
        current_transaction.size(), previous_output_script.data(),
        previous_output_script.size(), input_index32, flags);

    const auto valid = (result == verify_result::verify_result_eval_true);
#else
    // Copy the const prevout script so it can be run.
    auto previous_output_script = prevout_script;
    const auto& current_input_script = current_tx.inputs[input_index].script;

    const auto valid = script::verify(current_input_script,
        previous_output_script, current_tx, input_index32, bip16_enabled);
#endif

    if (!valid)
        log::warning(LOG_VALIDATE) << "Invalid transaction ["
        << encode_hash(current_tx.hash()) << "]";

    return valid;
}

void unspent_outputs::add(const transaction& tx, size_t height,
    uint32_t median_time_past, bool confirmed)
{
    if (disabled() || tx.outputs().empty())
        return;

    if (tx.is_coinbase())
    {
        LOG_DEBUG(LOG_DATABASE)
            << "Output cache hit rate: " << hit_rate() << ", size: " << size();
    }

    // Critical Section
    ///////////////////////////////////////////////////////////////////////////
    unique_lock lock(mutex_);

    // It's been a long time since the last restart (~16 years).
    if (sequence_ == max_uint32)
        unspent_.clear();

    // Remove the oldest entry if the buffer is at capacity.
    if (unspent_.size() >= capacity_)
        unspent_.right.erase(unspent_.right.begin());

    // TODO: promote the unconfirmed tx cache instead of replacing it.
    // A confirmed tx may replace the same unconfirmed tx here.
    unspent_.insert(
    {
        unspent_transaction{ tx, height, median_time_past, confirmed },
        ++sequence_
    });
    ///////////////////////////////////////////////////////////////////////////
}

bool db_tx::read_disk_transaction(
    const sha256 & hash, transaction & tx, transaction_index & index
    )
{
    assert(globals::instance().is_client() == false);
    
    tx.set_null();
    
    if (read_transaction_index(hash, index) == false)
    {
        return false;
    }
    
    return tx.read_from_disk(index.get_transaction_position());
}

bool validate_transaction::connect_input(const transaction& tx,
    size_t current_input, const transaction& previous_tx,
    size_t parent_height, size_t last_block_height, uint64_t& value_in)
{
    const auto& input = tx.inputs[current_input];
    const auto& previous_outpoint = tx.inputs[current_input].previous_output;
    if (previous_outpoint.index >= previous_tx.outputs.size())
        return false;

    const auto& previous_output = previous_tx.outputs[previous_outpoint.index];
    const auto output_value = previous_output.value;
    if (output_value > max_money())
        return false;

    if (previous_tx.is_coinbase())
    {
        const auto height_difference = last_block_height - parent_height;
        if (height_difference < coinbase_maturity)
            return false;
    }

    if (!check_consensus(previous_output.script, tx, current_input))
        return false;

    value_in += output_value;
    return value_in <= max_money();
}

void wallet_manager::sync_with_wallets(
    const transaction & tx, block * blk, const bool & update,
    const bool & connect
    )
{
    if (connect == false)
    {
        /**
         * Wallets need to refund inputs when disconnecting coinstake (ppcoin).
         */
        if (tx.is_coin_stake())
        {
            std::lock_guard<std::mutex> l1(mutex_);
            
            for (auto & i : m_wallets)
            {
                if (i->is_from_me(tx))
                {
                    i->disable_transaction(tx);
                }
            }
        }
    }
    else
    {
        std::lock_guard<std::mutex> l1(mutex_);
        
        for (auto & i : m_wallets)
        {
            i->add_to_wallet_if_involving_me(tx, blk, update);
        }
    }
}

void ExceptAndBackOffOnAbortNoticeCM::abort_on_write
(transaction &t, base_transaction_object const &in)
{
   //SLEEP(initialSleepTime_);
   t.lock_and_abort();
   throw aborted_transaction_exception("aborting transaction");
}

bool utility::get_transaction(
    const sha256 & hash_tx, transaction & tx, sha256 & hash_block_out
    )
{
    if (transaction_pool::instance().exists(hash_tx))
    {
        tx = transaction_pool::instance().lookup(hash_tx);
        
        return true;
    }
    
    db_tx tx_db("r");
    
    transaction_index index;
    
    if (tx.read_from_disk(tx_db, point_out(hash_tx, 0), index))
    {
        block blk;
        
        if (
            blk.read_from_disk(index.get_transaction_position().file_index(),
            index.get_transaction_position().block_position(), false)
            )
        {
            hash_block_out = blk.get_hash();
        }
        
        return true;
    }
    
    return false;
}

// Validate script consensus conformance based on flags provided.
bool validate_transaction::check_consensus(const script& prevout_script,
    const transaction& current_tx, size_t input_index, uint32_t flags)
{
    BITCOIN_ASSERT(input_index <= max_uint32);
    BITCOIN_ASSERT(input_index < current_tx.inputs.size());
    const auto input_index32 = static_cast<uint32_t>(input_index);

#ifdef WITH_CONSENSUS
    using namespace bc::consensus;
    const auto previous_output_script = prevout_script.to_data(false);
    data_chunk current_transaction = current_tx.to_data();

    // Convert native flags to libbitcoin-consensus flags.
    uint32_t consensus_flags = verify_flags_none;

    if ((flags & script_context::bip16_enabled) != 0)
        consensus_flags |= verify_flags_p2sh;

    if ((flags & script_context::bip65_enabled) != 0)
        consensus_flags |= verify_flags_checklocktimeverify;

    if ((flags & script_context::bip66_enabled) != 0)
        consensus_flags |= verify_flags_dersig;

    const auto result = verify_script(current_transaction.data(),
        current_transaction.size(), previous_output_script.data(),
        previous_output_script.size(), input_index32, consensus_flags);

    const auto valid = (result == verify_result::verify_result_eval_true);
#else
    // Copy the const prevout script so it can be run.
    auto previous_output_script = prevout_script;
    const auto& current_input_script = current_tx.inputs[input_index].script;

    const auto valid = script::verify(current_input_script,
        previous_output_script, current_tx, input_index32, flags);
#endif

    if (!valid)
        log::warning(LOG_BLOCKCHAIN)
            << "Invalid transaction ["
            << encode_hash(current_tx.hash()) << "]";

    return valid;
}

// TODO: cache transaction wire serialization.
code validate_input::verify_script(const transaction& tx, uint32_t input_index,
    uint32_t forks, bool use_libconsensus)
{
    if (!use_libconsensus)
        return script::verify(tx, input_index, forks);

    BITCOIN_ASSERT(input_index < tx.inputs().size());
    const auto& prevout = tx.inputs()[input_index].previous_output().metadata;
    const auto script_data = prevout.cache.script().to_data(false);
    const auto prevout_value = prevout.cache.value();

    const auto tx_data = tx.to_data(true, true);

    // libconsensus
    return convert_result(consensus::verify_script(tx_data.data(),
        tx_data.size(), script_data.data(), script_data.size(), prevout_value,
        input_index, convert_flags(forks)));
}

// A new transaction has been received, add it to the memory pool.
void transaction_pool::add(const transaction& tx, confirm_handler handler)
{
    // When a new tx is added to the buffer drop the oldest.
    if (maintain_consistency_ && buffer_.size() == buffer_.capacity())
        delete_package(error::pool_filled);

    // Store a precomputed tx hash to make lookups faster.
    buffer_.push_back({ tx.hash(), tx, handler });
}

void solve( transaction t ) {
    std::multiset<int> list = {2100000001};
    auto ref = list.insert( 2000000001 );
    /* ref é um "ponteiro" que apontará para o valor que será o próximo
     * i-ésimo da lista, a ser escrito no caso de um GET.
     * Apenas deslocaremos ref para frente e para trás, de acordo com
     * o inteiro que estamos inserindo. */

    while( !t.end() )
        if( t.add() ) {
            int k = t.next();
            list.insert( k );
            if( k < *ref )
                --ref;
        }
        else {
            printf( "%i\n", *ref );
            ++ref;
        }
}

bool validate_transaction::tally_fees(const transaction& tx, uint64_t value_in,
    uint64_t& total_fees)
{
    const auto value_out = tx.total_output_value();

    if (value_in < value_out)
        return false;

    const auto fee = value_in - value_out;
    total_fees += fee;
    return total_fees <= max_money();
}

bool db_tx::erase_transaction_index(const transaction & tx) const
{
    std::string key_tx = "tx";
    
    data_buffer buffer;

    buffer.write_var_int(key_tx.size());
    buffer.write_bytes(key_tx.data(), key_tx.size());
    
    buffer.write_sha256(tx.get_hash());

    return erase(buffer);
}

code validate_transaction::check_transaction(const transaction& tx)
{
    if (tx.inputs.empty() || tx.outputs.empty())
        return error::empty_transaction;

    if (tx.serialized_size() > max_transaction_size)
        return error::size_limits;

    // Check for negative or overflow output values
    uint64_t total_output_value = 0;
    for (const auto& output: tx.outputs)
    {
        if (output.value > max_money())
            return error::output_value_overflow;

        total_output_value += output.value;
        if (total_output_value > max_money())
            return error::output_value_overflow;
    }

    if (tx.is_coinbase())
    {
        const auto& coinbase_script = tx.inputs[0].script;
        const auto coinbase_size = coinbase_script.serialized_size(false);
        if (coinbase_size < 2 || coinbase_size > 100)
            return error::invalid_coinbase_script_size;
    }
    else
    {
        for (const auto& input: tx.inputs)
            if (input.previous_output.is_null())
                return error::previous_output_null;
    }

    return error::success;
}

void unspent_outputs::add(const transaction& transaction, size_t height)
{
    if (capacity_ == 0 || transaction.outputs().empty())
        return;

    // Critical Section
    ///////////////////////////////////////////////////////////////////////////
    unique_lock lock(mutex_);

    // It's been a long time since the last restart (~16 years).
    if (sequence_ == max_uint32)
        unspent_.clear();

    // Remove the oldest entry if the buffer is at capacity.
    if (unspent_.size() >= capacity_)
        unspent_.right.erase(unspent_.right.begin());

    unspent_.insert(
    {
        unspent_transaction{ transaction, height },
        ++sequence_
    });
    ///////////////////////////////////////////////////////////////////////////
}